drm/msm: allow rsc clients to wait on crtc id on transition

Add an API to the RSC state update function to give
responsibility of waiting on a VBLANK after RSC state transition
to the caller rather than RSC itself. This is due to RSC not
having the correct ability to wait for VBLANK on the correct
thread, instead the SDE encoder has that ability. SDE encoder is
also the only client type that needs to execute the wait.

This necessarily breaks up the encoder disable callflow to be
able to correctly transition the RSC to the IDLE state before
the physical encoders are transitioned to the disabled state.

Change-Id: I3e44c5d0e56dfc4c60eb7f53ca29898576efd399
Signed-off-by: Lloyd Atkinson <latkinso@codeaurora.org>